Supercontinua extending from the ultraviolet to the infrared are observed from high-pressure (1-40 atm) Ar, Kr, Xe, H2, N2, or CO2 illuminated with 2-psec or 70-fsec, 0.6-m pulses with an energy 500 ÄJ. The blue spectral component is shown to display a nearly universal behavior for all gases and pulse durations. Although the maximum intensity of the focused, femtosecond pulse in an evacuated cell was ̂Ä1013 W/cm2, continuum generation was only observed with the femtosecond pulse when the threshold for self-focusing was exceeded.